As found! This is a glacial concretion made of sand, calcium carbonate, clay and naturally solidified.
The squiggles or textures were left from other fossils or worms etc!
Designed by Mother Nature! From Wikipedia:” A concretion is a hard, compact mass of matter formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular shapes also occur.”
This one looks like a sea otter to me!